1. Field
This invention relates generally to radioassays and specifically to a solid phase radioimmunoassay for the detection and/or quantitation of viral antibodies.
2. Prior Art
Viral antibodies can be detected and quantitated by the so-called viral neutralization methods which may take up to 2 weeks to perform. A relatively recent method for determining Human Immunoglobulins is disclosed by S. E. Salmon et al. in an article entitled "Sandwich Solid Phase Radioimmunoassay for the Quantitative Determination of Human Immunoglobulins", in J. Immunol., 103, 129-137 (1969). In U.S. Pat. No. 3,652,761 issued to H. H. Weetall on March 28, 1972, there is disclosed a method of isolating antibodies from a solution. The method involves reacting the solution with an immunochemical composite consisting of an appropriate antigenic substance coupled through an intermediate silane coupling agent to an iorganic carrier such as porous glass particles. By employing teachings in the above patent, it is possible to successfully couple antigenic substances such as viruses or virions to an inorganic support and use the resulting composite to extract corresponding specific antibodies from a solution. In preparing immobilized virus composites, it is desirable to achieve a fairly high loading of the virus on the carrier material. To a certain extent, such high loadings can be accomplished by using high surface area carriers such as porous glass particles. Unfortunately, however, many virus or virion preparations contain numerous other materials as impurities and those impurities may take part in the binding process, thus limiting the amount of virus that can be bound on the high surface area carrier. We have now found that by critically modifying the broad teachings of U.S. Pat. No. 3,652,761 and employing recent solid phase radioimmunoassay techniques, it is possible to load sufficient quantities of viruses or virions on porous glass particles such that it is possible to detect and quantitate viral antibodies in less than one day. Our method, and its use to detect and quantitate two types of equine anti-influenza virus antibodies is described in detail below.